Events Quick Guide

Events are actions or occurrences that happen in a system, which generate a notification to subscribers. The message to subscribers that something has happened typically initiates an appropriate response from the recipient, generating subsequent actions or processing.

At Temenos, we use Events to indicate a status change in one of our solutions or products, like an action occurring in Buy Now Pay Later, Retail Banking or Wealth Management. The Event triggers a message so our code can react to it with an appropriate response.

What exactly is an Event?

It's something significant like a change in state — an update in an application that generates value to someone or something, for example, a purchase made by credit card is an Event. A customer checking their account balance is also an Event.

How are Events created?

Events are triggered in banks and financial institutions constantly, including every time someone:

  • Makes a loan repayment
  • Opens or closes an account
  • Uses their debit card

Events can happen by clicking a mouse, pressing a button on an ATM or selecting Enter on a keyboard. Also, they can happen automatically and be generated by an API. The message created by the Event is known as the 'Event notification'.

What happens when an Event takes place?

Once an Event occurs, a message is generated in JSON format and posted on a topic. If a developer writes an application that subscribes to that topic, the application is notified the Event has been triggered. In response to the Event, the application can perform any relevant processing.

Does the message or Event notification happen immediately?

No. The notification doesn't necessarily happen at the same time or immediately after the Event; the communication pattern is described as 'asynchronous', which means that a developer needs to subscribe to be notified.

How do you subscribe to a topic?

Using Middleware like Kafka, which enables multiple systems to communicate with each other across different platforms. 

What is Kafka?

It's an asynchronous communication system, known as Pub/Sub or Publish/Subscribe. It's designed for applications to exchange messages, providing a form of communication between publishers and receivers on topics they subscribe to.

How do Events work?

Kafka (and Event Notifications) are similar to an electronic mailout: subscribers behave differently when they're notified. Some will ignore or delete it; some will ask to unsubscribe from the mailing list; and some will respond — some complain, some enquire, some buy. The same message goes to the whole list but everyone can respond differently. For example, a developer could subscribe to loan events and trigger some processing every time a loan is created or every time a payment is made. Developers can subscribe to whichever topics are of interest and react to them when they're triggered. Each entity within the system has a lifecycle and different events can happen at different stages of that lifecycle.

Frequently Asked Questions


What's the difference between an API and an Event?

  • APIs use online interactions where applications require instant feedback for the actions performed.

  • Events use asynchronous communications where applications don't require instant feedback.

Although different, the two are complementary and together both technologies combined are extremely powerful. Temenos uses both APIs and Events to design business solutions.

Are there changes which are not considered Events?

Yes. To be considered an Event the change needs to be 'significant'. Events should always be tied to meaningful business value.

Do you need Temenos Workbench for Events?

No. If you're subscribed to a topic, every time a message appears on that topic, you receive a notification in your program and you can either ignore it or respond and carry out some processing.

More information

See Events Overview

See Events Architectures

See Apache Kafka